Crushing machine for hard materials



Jfily 9, 1929. J. lH LE FELDT CRUSHING MACHINE FOR HARD MATERIALS Filed June 2'7. 1927 lf/arney.

Patented July 9, 1929.

UNITED STATES 1,719,979 PATENT OFFICE.

J'OHANNES IHLEFELDT, OF DESSAU, GERMANY, ASSIGNOR TO G. POLYSIUS, OF DESSAU, GERMANY, A FIRM OF GERMANY.

CRUSHING MACHINE FOR HARD MATERIALS.

Application filed June 27, 1927, Serial No. 201.897, and in Germany February 4, 1926.

My invention relates to an improvement in the type of crushing machines for hard materials which is known under the name of ring roller mill or kneading mill. This mill which is particularly useful for reducing phosphorites is much appreciated as a device which operates noiselessly and cheaply, requires no brick foundation, asv is able to deal with coarse grained materials and even moist corn without any sifting device.

The disadvantage of this type of mill, 18, however, that they furnish a granular product only. If a finer productis desired it is necessary to provide behind the mill a sifting device (air sifter, cyclone or sieve) for'returning the granules detainedto the mill. A very bulky set of machines thus becomes necessary for the crushing process, comprising conveyors, bucket elevators andthe like.

this disadvantage and to obtain a fine uniform product directly after the first pass of the material through the millv without being obliged to use any additional apparatus.

The invention consists substantially in combining a ring roller mill with a grinding mill. In the embodiment described hereafter this is attained by constructing-the crushing ring so that it functions at the same time as grinding ring which rotates between two non-rotatable grinding rings forced against it by springs or elastic cushions. The distance of these non-rotatable grinding rings from the rotating crushing ring is adapted'to be adjusted to enablethe regulation of the de- 'gree of reduction of the product. As the wear of the grinding ring and the rotating crushing ring is different, they are preferably not made in a single piece, but the grind- 0 ing ring-is constructed as a separate part and detachably mounted upon the crushing ring.

It is furthermore advisable to bevel the friction rings towards one side or both sides, since the material issuing under the action of the centrifugal force is subjected to a brake action by the friction against the outer bevel and is thus more forcibly employed to the grinding action. In contrast with the hitherto known constructions of ring roller mills in which the drive of the crushing ring takes place indirectly by the aid ofthe u permost crushing roller or bowl, the crus ing ring according to my invention, is driven directly because in the event of a finer adjust- The object of my invention is to eliminate proved mill,

rotates .withsaid rollers m. The material,

ment of the grinding space between the grinding wheels the indirect drive would hardly be able to overcome the resistance set up by the increased friction. The direct drive is preferably effected by a centrally disposed shaft, projecting from the casing of the mill. The grinding ring is connected with this shaft by a spider to render the direct drive of the grinding ring possible on the one hand, and on the other hand to make the support of grinding rollers more elastic and to improve the accessibility of the interior of grinding chamber, the grinding rollers are supported at one side only in contrast with the well known kneading'mills.

Two embodiments of 'my invention are illustrated in the drawing affixed hereto, by way ofexample.

In the drawing is: i

Fig. 1 a cross-section through my im- H F ig. 2 a side-view taken on Fig. 1, Fig. 3 a longitudinal section through asomewhat modified construction and-Fig. 4

. a side-view on Fig. 3.

Referring to the drawing, it will be seen that within a rotary crushing ring a revolve a plurality of grinding rollers m. In both designs of my improved machine the drive is effected by the shaft 'w upon which is mounted a pulley 6. Against the grinding ring 6, made in one. piece with the crushing ring a (Fig. 1) or removably supported upon it (Fig. 3) abut the I non-rotatable grinding rings-(Z, (2' under the pressure of spring a. In order to properly adjust the gap between the rotating and stationary friction rings b and d the springs a may be provided with an adjusting device 9, as illustrated in Fig. 3 of the drawing.

The mode of operation of the combined rin roller crushing and grinding mill according to my invention is as follows: On account ofthe fa'ctthat the crushing ring is constructed to operate simultaneousl as a grinding ring, which is accomplishe by having two stationar grinding rings associated with said crus ing ring, the crushing of the material takes place intermediate the grind ing rollers m and the crushing. ring a which after having thus passed the crushing operation, is now conveyed for the purpose of subsequent treatment which consists essentially in a grinding operation, intermediate the rotary crushing ring a and the stationary grinding rings d. The rings (1 are pressed against the rotary crushing ring a with a greater or smaller degree of play by means of the springs 0. By adjusting this play the material may be ground to any desired fineness subsequent to the crushing operation.

I claim:

1. A combined ring roller crushing and grinding mill, comprising in combination, a rotary crushing ring adapted to operate at the same time as grinding ring, a non-rotatable grinding ring located at each side of said combined crushing and grinding ring, and means for pressing said non-rotatable grinding rings resiliently towards said rotary rln 2. A combined ring roller crushing and grinding mill, comprising in combinatlon, a

rotary crushing ring adapted to operate at the same time as grinding ring, a non-rotat-' able grinding ring located at each side of said zolnbined crushing and grinding ring, springs for pressing said non-rotatable grinding rings resiliently towards said rotary ring, and means for adjusting the widths of the gaps between both sets of rings.

3. A combined ring roller crushing and grinding mill, comprising in combination, a rotary crushing ring, a rotary detachable grinding ring mounted upon said crushing ring, a non-rotatable grinding ring located at each side of said rotary grinding ring, means for pressing said non-rotatable rings towards said rotary ring, and means for adjusting the widths of the gaps between both sets of rings.

4. A combined ring roller crushing and grindipg mill, comprising, a rotary crushing ring adapted to operate at the same time as grinding ring, a non-rotatable grinding ring with inclined inner face located at each side of said combined crushing and grinding ring,a'nd means for pressing said nonrotatable grinding rings resiliently towards said rotary ring.

5. A combined ring roller crushing and grinding mill,compr1sing in combination, a rotary crushing ring, a rotary detachable grinding ring mounted upon said crushing ring, a non-rotatable grinding ring with-inclined inner face located at each side of said rotary grinding ring, means for pressing said non-rotatable rings towards said rotary ring, and means for adjusting the widths of the gaps between both sets of rings.

6. A combined ring roller crushing and grinding mill, comprising in combination, a rotary crushing ring, a rotary detachable grinding ring with inclined outer faces mounted upon said crushing ring, a non-rotatable grinding ringwith inclined inner face located at each side of said rotary grinding ring, means for pressing said non-rotatable rings towards said rotary ring, and means for adjusting the widths of the gaps between both sets of rings.

7. A combined ring roller crushing and grinding mill, comprising a rotary crushing ring, crushing rollers associated therewith, driving means for one of the crushing rollers which in its turn drives the crushing ring adapted to operate at the same time as grindingring, a non-rotatable grinding ring located at each side of said compound rotary ring, and means for pressing said non-rotatable rings towards said rotary crushing ring.

8. A combined ring roller crushing and grinding mill, comprising a plurality of crushing rollers, a crushing ring mounted upon said rollers, a grinding ring detachably mounted upon said crushing ring, a central driving shaft, a spider fixed upon said driving shaftand attached to said grinding ring, a non-rotatable grinding ring on each side of said rotary grinding'ring, and resilient means for forcing both sets of rings together.

9. A combined ring roller crushing and grinding mill, comprising a plurality of crushing rollers journalled at one side of the machine only, a crushing ring mounted upon said rollers, a grinding rlng detachably mounted upon said crushing ring, a central driving shaft, a spider fixed upon said driving shaft and attached to said grinding ring,

a non-rotatable grinding ring on each side of said rotary grinding ring, and resilient means for forcing both sets of rings together.

In testimony whereof I afiix my signature JOHANNES IHLEFELDT. 

